Combined surgical-orthodontic and prosthetic treatment of a partially edentulous patient with skeletal Class III malocclusion

学術論文(Ariticle)journal articl

Decreased alveolar bone turnover is related to the occurrence of root resorption during experimental tooth movement in dogs

Objective:  To investigate the relationship between root resorption (RR) and bone turnover in two different types of tooth movement in dogs. Materials and Methods:  A total of 16 dogs in two different groups were used. Tooth movement of dog premolars resulted from approximately 200 g of force. Histomorphometric analysis of premolar roots was assessed after 4 and 12 weeks of tooth movement by comparing nonresorptive to resorptive surfaces. Results:  Histomorphometric analysis indicated a significant decrease in the bone formation rate in the root resorptive areas, which resulted in decreased bone volume after 12 weeks. The threshold to detect RR in periapical radiographs was about 1.0 mm2. Conclusions:  A sustained mechanical load, due to the prolonged stress and strain of continuous mechanics, induces elevated bone metabolic activity, such as the bone turnover (remodeling) and change in bone volume (modeling). Therefore, our data support the hypothesis that increased RR is related to decreased bone formation (turnover) in high stress areas exposed to prolonged orthodontic tooth movement

Improvement of Open Bite and Stomatognathic Function in an Axenfeld- Rieger Syndrome Patient by Orthodontic Sectional Arch Mechanics: Clinical Considerations and the Risk of Orthodontic Tooth Movement

Orthodontists need to understand the orthodontic risks associated with systemic disorders. Axenfeld-Rieger syndrome (ARS) is a rare autosomal dominant disorder with genetic and morphological variability. The risks of orthodontic treatment in ARS patients have been unclear. Here we describe the correction of an anterior open bite in a 15-year-old Japanese female ARS patient by molar intrusion using sectional archwires with miniscrew implants. An undesirable development of external apical root resorption (EARR) was observed in all intrusive force-applied posterior teeth during the patient’s orthodontic treatment, suggesting that ARS patients have a higher risk of EARR than the general population

Insulin-like growth factor 1 modulates bioengineered tooth morphogenesis

Regenerative therapy to replace missing teeth is a critical area of research. Functional bioengineered teeth have been produced by the organ germ method using mouse tooth germ cells. However, these bioengineered teeth are significantly smaller in size and exhibit an abnormal crown shape when compared with natural teeth. The proper sizes and shapes of teeth contribute to their normal function. Therefore, a method is needed to control the morphology of bioengineered teeth. Here, we investigated whether insulin-like growth factor 1 (IGF1) can regulate the sizes and shapes of bioengineered teeth, and assessed underlying mechanisms of such regulation. IGF1 treatment significantly increased the size of bioengineered tooth germs, while preserving normal tooth histology. IGF1-treated bioengineered teeth, which were developed from bioengineered tooth germs in subrenal capsules and jawbones, showed increased sizes and cusp numbers. IGF1 increased the number of fibroblast growth factor (Fgf4)-expressing enamel knots in bioengineered tooth germs and enhanced the proliferation and differentiation of dental epithelial and mesenchymal cells. This study is the first to reveal that IGF1 increases the sizes and cusp numbers of bioengineered teeth via the induction of enamel knot formation, as well as the proliferation and differentiation of dental epithelial and mesenchymal cells